1. Field of the Invention
The present invention relates to pyrrole compounds, polymers thereof which can be used as a material for an organic polymer semiconductor and optical electronic material, and in particular, as a core material for an organic and polymeric electroluminescence (referred to as xe2x80x9cELxe2x80x9d, hereinafter) element, and to an EL element using the same.
2. Description of the Background Art
Poly(phenylenevinylene) (referred to as xe2x80x9cPPVxe2x80x9d, hereinafter), polythiophene (referred to as xe2x80x9cPThxe2x80x9d, hereinafter) and polyphenylene group polymers (d 2F Nature, 4 7, p549 (1990), Synth. Met., 50(1-3), p491 (1992); Adv. Mater., 4, p36 (1992); Adv. Mater., 6, p190 (1994); and Chem. Rev., 99, p1747 (1999)) have been widely and representatively known as organic polymer semiconductor and optical electronic materials (See Semiconducting Polymers: Chemistry, Physics and Engineering, Edited by G. Hadziioannou and P. F. van Hutten, WILEY-VCH (2000)) or as polymer light-emitting materials (Angew, Chem, Int. Ed., 37, p402 (1998); Nature, 397, p121 (1999); Prog. Polym. Sci., 25, p1089 (2000); and Adv. Mater., 12, p1737 (2000)). However, such polymer materials in which researches have been conducted into up to now have shortcomings that final products are not dissolved in an organic solvent.
There have been known PPV or PTh derivatives which emit lights of blue, green and red, and have an improved processibility by introducing a suitable substituent thereto (Synth. Met., 62, p35 (1994); Adv. Mater., 4, p36 (1992); and Macromolecules, 28, p7525 (1995)), and some of which exhibit an excellent processibility since they can be easily dissolved in an organic solvent even though they have a large molecular weight (Adv. Mater., 10, p1340 (1998)).
Recently, fluorene group polymers have been reported frequently as light-emitting materials (See Jpn. J. Appl. Phys., 30, pL1941 (1991); J. Polym. Sci. Polym. Chem. Ed., 31, p2465 (1993); J. Am. Chem. Soc., 118, 7416 (1996); Adv. Mater., 9, p326 (1997); Adv. Mater., 10, p993 (1998); Macromolecules, 32, p1476 (1999); Nature, 405, p661 (2000); Synth. Met., 111-112, p397 (2000); Synth. Met., 122, p79 (2001) and J. Am. Chem. Soc., 123, 946 (2001)).
In addition, there are U.S. Pat. Nos. 5,621,131, 5,708,130 and 5,900,327 which disclose fluorene group polymers having a single bond, and U.S. Pat. No. 5,807,974 which discloses a fluorene group alternate copolymer having a conjugate double bond as a light-emitting material for an EL element.
Polymers having an acetylene group have been presented as an organic polymer semiconductor and optical electronic material (See Makromol. Chem., 191, p857 (1990); Macromolecules, 27, p562 (1994); J. Chem. Soc., Chem. Commun., p1433 (1995); and Macromolecules, 29, p5157 (1996)), which mostly relate to a nonlinear optical material, a photoconductivity and photoluminescence (hereinafter referred to as xe2x80x9cPLxe2x80x9d) material. Among them, Synth. Met., 102, p933 (1999) discloses an example used as an EL material, and researches into other applications have been also reported (See Science, 297, p835 (1998)). Polymers having a diacetylene group have been also reported (See Prog. Polym. Sci., 20, p943 (1995); CHEMTECH, October P32 (1993); Macromolecules, 29, p2885 (1996); Synth. Met., 111-112, p429 (2000); and Synth. Met., 119, p105 (2001)). These polymers are so sensitive to heat or light, like the above acetylene group polymers, that they can be easily cross-linked, so as to enable to obtain stable cross-linked polymers. Applications of polymers having an acetylene or diacetylene group as EL materials have been patented to the applicant of the present invention (U.S. Pat. Nos. 5,876,864 and 6,344,286).
However, until now, organic light-emitting diodes using organic complex such as Alq3 or Ir(Ppy)3, rather than polymers, have been commercialized as organic EL materials (U.S. Pat. Nos. 4,356, 429 and 5,061,569; Appl. Phys. Lett., 51, p913 (1987); SID Digest, 27, p849 (1996); Nature, 395, p161 (1998); and Nature, 403, p750 (2000)).
There have not been reported any blue light emitting polymers, including a fluorene group polymer, which shows good enough performances in efficiency and life of element to be commercialized, except for some green and orange color emitting PPV group polymers exhibiting excellent characteristics (Adv. Mater., 10, p1340 (1998)). Therefore, it is still expected a novel organic and polymer EL material, which can ensure highest efficiency and maximize stable life of an element, to be presented.
Polyaniline, polypyrrole and derivatives thereof which have been known as conducting materials (Handbook of Conducting Polymers, Edited by T. A. Skotheim, Marcel Dekker (1986)) are only subjected to researches for using antistatic, electrode and chromic materials, and their applications as light emitting materials can be rarely found.
Therefore, an object of the present invention is to provide novel pyrrole compounds and polymers thereof, in which their structure can be identified, and which can be well dissolved in an organic solvent and can be applied as EL and other optical electronic materials.
Another object of the present invention is to provide an EL element using the above pyrrole compounds and/or polymers thereof as a core material.
The foregoing and other features, aspects and advantages of the present invention will become more apparent from the following detailed description of the present invention when taken in conjunction with the accompanying drawings.
A pyrrole compound and polymers thereof according to the present invention are represented by the following chemical formula (1): 
wherein, m is 0 or an integer of above 1, and n is an integer of above 1;
R1 and R2 are substituents which are the same with or different from each other, and includes hydrogen, C1-C22 aliphatic alkyl, C1-C22 alicyclic alkyl, C1-C22 acyl and C1-C22 alkoxy, C6-C30 aryl or aryloxy, a halogen containing substituent, silicon containing substituents, organic acid and ester of organic acid, but not limited thereto, and in more detail, R1 and R2 can be independently selected from the group consisting of hydrogen, methyl, ethyl, propyl, isopropyl, butyl, isobutyl, pentyl, hexyl, ethylhexyl, heptyl, octyl, isooctyl, nonyl, decyl, dodecyl, hexadecyl, octadecyl, docodecyl, cyclopropyl, cyclopentyl, cyclohexyl, acetyl, octanoyl, benzoyl, methoxy, ethoxy, etylenedioxy, buthoxy, hexyloxy, methoxyethoxyethyl, methoxyethoxyethoxyethyl, cyanoethyl, carboxymethyl, phenyl, phenoxy, tolyl, benzyl, naphthyl, anthracenyl, terphenyl, pyrenyl, diphenylanthracenyl, pentacenyl and derivatives thereof, chloride, bromide, iodide, bromomethyl, trimethylsilyl, dimethyloctylsilyl, and butylsulfonic acid, propionic acid and methyl esters thereof;
Ar1, Ar2 and Ar3 are the same or different aromatic group, respectively selected from the group consisting of C6-C30 aromatic group, or halogen, metal or hetero atom-containing C6-C30 aryl group, and examples include phenyl, tolyl, naphthyl, stilbenyl, fluorenyl, anthracenyl, terphenyl, pyrenyl, diphenylanthracenyl, dinaphthylanthracenyl, pentacenyl and derivatives thereof, bromophenyl, hydroxyphenyl, thienyl, pyridyl, azobenzenyl, ferrocenyl, carbazoyl, porphyrinyl and derivatives thereof; and
Arxe2x80x2 is an aromatic or heterocyclic group such as phenyl, naphthyl, anthracenyl, fluorenyl, thiopenyl, pyrrolyl, pyridinyl, aryloxadiazolyl, triazolyl, carbazolyl, arylamino, arylsilano or derivatives thereof, but not limited thereto, and especially preferable examples include the groups represented by the following chemical formulae: 
wherein, R1 and R2 are the same substituents as described in the above chemical formula (1).
The pyrrole compounds and polymers thereof of the present invention include a reaction or polymerization product between the same or different pyrrole compounds of the present invention, and a reaction or polymerization product between the pyrrole compounds of the present invention and other organic compound. The kinds of the compounds and polymers thereof of the present invention are not specially limited, and any pyrrole compounds and polymers thereof are included so long as it can be easily prepared and have excellent EL properties.
The pyrrole compounds and polymers thereof according to the present invention can be prepared through the following reaction schemes 1 to 14: 
However, in addition to the above-described method, if final products are the same, any known methods can be applied to prepare pyrrole compounds and polymers thereof of the present invention. That is, in preparation of the pyrrole compounds and/or polymers thereof according to the present invention, a solvent, reaction temperature, concentration of reactants, catalyst or the like may not be specifically limited to those as shown in the above reaction schemes, and likewise the preparation yield.
The organic and polymer EL element and/or other optical devices of the present invention can be fabricated using the compound and polymers thereof having structures as shown in the Reaction Schemes 1 through 14 as a core material.
The pyrrole compounds or polymers thereof of the present invention can be made into a thin film by a know method such as vacuum-deposition, spin-coating, roll-coating, bar-coating, ink-jet printing or the like, and then can be directly used as an EL material.
In the structure, the EL element of the present invention include not only an EL element of a typical single-layered structure consisting of anode/light-emitting layer/cathode in which a light-emitting layer material is inserted between an anode and a cathode, but also an EL element of a multi-layered structure consisting of anode/hole transporting layer/light-emitting layer/electron transporting layer/cathode in which a hole transporting layer and an electron transporting layer material (Japanese Laid Open No. 2-135361, 3-152184 and 6-207170) are additionally used.
In one embodiment of the present invention, an EL element can be made to have a structure of anode/hole injection layer/hole transporting layer/light-emitting layer/electron transporting layer/cathode, in which poly(ethylenedioxy)thiophene (PEDOT), polyaniline, copper phthalocyanine (CuPc) or the like widely known as a hole injection layer material is located between the anode and the hole transporting layer. That is, in the present invention, there is no limitation on structures of the EL element.
Furthermore, in addition to as a material for the light-emitting layer, the pyrrole compounds and/or polymers thereof according to the present invention can be used as a core material for a hole transporting layer and/or electron transporting layer, or a hole injection layer of an EL element.
In the EL element of the present invention, a material in which a metal or metallic oxide such as indium-tin oxide (ITO), gold, copper, tin oxide or zinc oxide, or an organic semi-conducting compound such as polypyrrole, polyaniline or polythiopene is coated onto a transparent support substrate such as glass, transparent plastic or quartz, usually at a thickness of 10 nm to 1 xcexcm, can be used as an anode. As a cathode, a metal such as sodium, magnesium, calcium, aluminum, indium, silver, gold or copper, or alloys thereof can be used.
In the EL element of a multi-layered structure, a material in which polyvinylcarbazole, 2,5-bis(4xe2x80x2-diethylaminophenyl)-1,3,4-oxadiazole, N,Nxe2x80x2-diphenyl-N,Nxe2x80x2-(3-methylphenyl)-1,1xe2x80x2-biphenyl-4,4xe2x80x2-diamine (TPD) or the like is coated by a known thin film forming method such as a vacuum-depositing, spin-coating, casting or an LB method can be used as a hole transporting layer, and a material in which a known compound such as tris(8-hydroxyquinolynato)aluminum (referred to as xe2x80x9cAlq3xe2x80x9d, hereinafter), 2-(4xe2x80x2-t-butylphenyl)-5-(4xe2x80x3-biphenyl)-1,3,4-oxadiazole, 2,4,7-trinitro-9-florenone or the like is coated by a known thin film forming method such as a vacuum-depositing, spin-coating, casting or LB method can be used as an electron transporting layer.
An EL material comprising different kind of pyrrole compounds or polymers thereof according to the present invention can be used by being blended with the material for the hole transporting layer or electron transporting layer as described above; a soluble PPV or PTh, or derivatives thereof; known light-emitting material such as dinaphthyl anthracene compounds, tetra-t-butyl pyrene, spyrofluorene compounds or fluorene polymer; a doping material; or polymers thereof.
For example, a polymer according to the present invention can be dissolved together with polyvinylcarbazole, poly(1,4-dihexyloxy-2,5-phenylenevinylene), poly(9,9xe2x80x2-dioctylfluorene) or the like in an organic solvent such as chloroform, and then the resulting solution can be coated onto an anode, hole injection layer or hole transporting layer depending on the desired element structure by a spin-coating or casting method as a thin film. In this case, the amount of the light-emitting polymer of the present invention can be in the range of 0.001 to 99% and preferably, 0.1 to 50% of polyvinylcarbazole, and the thickness of the thin film can be in the range of 5 nm to 5 xcexcm and preferably, 50 nm to 1 xcexcm, but not limited thereto.
The EL material of the present invention can be used by being blended with a polymer that can be dissolved in a typical organic solvent in the above concentration and then can be made into a thin film in the above thickness range. Examples of the polymer which can be blended with the EL material of the present invention include a thermoplastic polymer such as polymethylmethacrylate, polyacrylate, polystyrene, polycarbonate, polyvinylchloride, polyethylene, polypropylene, polyacrylonitrile, polyvinylpyrrolidone, polyvinylalcohol, polyvinylacetate, polyvinylbutylal, polyvinylamine, polycaprolactone, polyethyleneterephtalate, polybutyleneterephtalate, polyurethane, ABS, polysulfone and polyvinylfluoride, and a commonly used resin such as acetal, polyamide, polyimide, polyester, alkid, urea, furan, nylon, melamine, phenol, silicone and epoxy.